Hypoplastic Circumflex Aorta With Anomalous Left Pulmonary Artery: Uncrossing Operation in a Neonate.

Circumflex aortic arch with coarctation and anomalous origin of the left pulmonary artery from the aorta are rare cardiovascular anomalies. These conditions can lead to early pulmonary hypertension and challenging management. Early diagnosis and surgical intervention are beneficial for optimal outcome. We present a case where both anomalies coexisted and were repaired with aortic uncrossing, arch augmentation, and reimplantation of the left pulmonary artery. To our knowledge, this is the first documented instance of these anomalies coexisting and being repaired in the neonatal period.

Association and Repair of Right Aortic Arch With Aberrant Left Subclavian Artery With Subclavian Stenosis.

Surgical repair of right aortic arch and aberrant left subclavian artery has traditionally involved ligamentum division. Such patients can have stenosis at the origin of the aberrant subclavian artery either at the time of presentation or later. The more recently popularized repair involving resection of Kommerell diverticulum with transfer of the subclavian artery to the left carotid artery allows resection of the stenotic segment and serves as an effective treatment for subclavian stenosis as well. We present three cases of early repair of this arch anomaly with associated subclavian stenosis repaired successfully in that manner.

Cardiac Biomarkers Aid in Differentiation of Kawasaki Disease from Multisystem Inflammatory Syndrome in Children Associated with COVID-19.

Kawasaki disease (KD) and Multisystem Inflammatory Syndrome in Children (MIS-C) associated with COVID-19 show clinical overlap and both lack definitive diagnostic testing, making differentiation challenging. We sought to determine how cardiac biomarkers might differentiate KD from MIS-C. The International Kawasaki Disease Registry enrolled contemporaneous KD and MIS-C pediatric patients from 42 sites from January 2020 through June 2022. The study population included 118 KD patients who met American Heart Association KD criteria and compared them to 946 MIS-C patients who met 2020 Centers for Disease Control and Prevention case definition. All included patients had at least one measurement of amino-terminal prohormone brain natriuretic peptide (NTproBNP) or cardiac troponin I (TnI), and echocardiography. Regression analyses were used to determine associations between cardiac biomarker levels, diagnosis, and cardiac involvement. Higher NTproBNP (≥ 1500 ng/L) and TnI (≥ 20 ng/L) at presentation were associated with MIS-C versus KD with specificity of 77 and 89%, respectively. Higher biomarker levels were associated with shock and intensive care unit admission; higher NTproBNP was associated with longer hospital length of stay. Lower left ventricular ejection fraction, more pronounced for MIS-C, was also associated with higher biomarker levels. Coronary artery involvement was not associated with either biomarker. Higher NTproBNP and TnI levels are suggestive of MIS-C versus KD and may be clinically useful in their differentiation. Consideration might be given to their inclusion in the routine evaluation of both conditions.

COVID-19 Positive Versus Negative Complete Kawasaki Disease: A Study from the International Kawasaki Disease Registry.

To determine clinical differences for children with complete Kawasaki disease (KD) with and without evidence of preceding SARS-CoV-2 infection. From January 2020, contemporaneous patients with complete KD criteria were classified as either SARS-CoV-2 positive (KDCOVID+; confirmed household exposure, positive PCR and/or serology) or SARS-CoV-2 negative (KDCOVID-; negative testing and no exposure) and compared. Of 744 patients in the International Kawasaki Disease Registry, 52 were KDCOVID- and 61 were KDCOVID+. KDCOVID+ patients were older (median 5.5 vs. 3.7 years; p < 0.001), and all additionally met diagnostic criteria for multisystem inflammatory syndrome in children (MIS-C). They were more likely to have abdominal pain (60% vs. 35%; p = 0.008) and headache (38% vs. 10%; p < 0.001) and had significantly higher CRP, troponin, and BUN/creatinine, and lower hemoglobin, platelets, and lymphocytes. KDCOVID+ patients were more likely to have shock (41% vs. 6%; p < 0.001), ICU admission (62% vs. 10%; p < 0.001), lower left ventricular ejection fraction (mean lowest LVEF 53% vs. 60%; p < 0.001), and to have received inotropic support (60% vs. 10%; p < 0.001). Both groups received IVIG (2 doses in 22% vs. 18%; p = 0.63), but KDCOVID+ were more likely to have received steroids (85% vs. 35%; p < 0.001) and anakinra (60% vs. 10%; p = 0.002). KDCOVID- patients were more likely to have medium/large coronary artery aneurysms (CAA, 12% vs. 0%; p = 0.01). KDCOVID+ patients differ from KDCOVID-, have more severe disease, and greater evidence of myocardial involvement and cardiovascular dysfunction rather than CAA. These patients may be a distinct KD phenotype in the presence of a prevalent specific trigger.

Emerging Insights Into the Pathophysiology of Multisystem Inflammatory Syndrome Associated With COVID-19 in Children.

Multisystem inflammatory syndrome in children (MIS-C) has emerged as a rare delayed hyperinflammatory response to SARS-CoV-2 infection and causes severe morbidity in the pediatric age group. Although MIS-C shares many clinical similarities to Kawasaki disease (KD), important differences in epidemiologic, clinical, immunologic, and potentially genetic factors exist and suggest potential differences in pathophysiology and points to be explored and explained. Epidemiologic features include male predominance, peak age of 6 to12 years, and specific racial or ethnicity predilections. MIS-C is characterized by fever, prominent gastrointestinal symptoms, mucocutaneous manifestations, respiratory symptoms, and neurologic complaints, and patients often present with shock. Cardiac complications are frequent and include ventricular dysfunction, valvular regurgitation, pericardial effusion, coronary artery dilation and aneurysms, conduction abnormalities, and arrhythmias. Emerging evidence regarding potential immunologic mechanisms suggest that an exaggerated T-cell response to a superantigen on the SARS-CoV-2 spike glycoprotein-as well as the formation of autoantibodies against cardiovascular, gastrointestinal, and endothelial antigens-are major contributors to the inflammatory milieu of MIS-C. Further studies are needed to determine both shared and distinct immunologic pathway(s) that underlie the pathogenesis of MIS-C vs both acute SARS-CoV-2 infection and KD. There is evidence to suggest that the rare risk of more benign mRNA vaccine-associated myopericarditis is outweighed by a reduced risk of more severe MIS-C. In the current review, we synthesize the published literature to describe associated factors and potential mechanisms regarding an increased risk of MIS-C and cardiac complications, provide insights into the underlying immunologic pathophysiology, and define similarities and differences with KD.

Accuracy of Cardiac Magnetic Resonance Imaging in Diagnosing Pediatric Cardiac Masses: A Multicenter Study.

BACKGROUND: After diagnosis of a cardiac mass, clinicians must weigh the benefits and risks of ascertaining a tissue diagnosis. Limited data are available on the accuracy of previously developed noninvasive pediatric cardiac magnetic resonance (CMR)-based diagnostic criteria. OBJECTIVES: The goals of this study were to: 1) evaluate the CMR characteristics of pediatric cardiac masses from a large international cohort; 2) test the accuracy of previously developed CMR-based diagnostic criteria; and 3) expand diagnostic criteria using new information. METHODS: CMR studies (children 0-18 years of age) with confirmatory histological and/or genetic diagnosis were analyzed by 2 reviewers, without knowledge of prior diagnosis. Diagnostic accuracy was graded as: 1) single correct diagnosis; 2) correct diagnosis among a differential; or 3) incorrect diagnosis. RESULTS: Of 213 cases, 174 (82%) had diagnoses that were represented in the previously published diagnostic criteria. In 70% of 174 cases, both reviewers achieved a single correct diagnosis (94% of fibromas, 71% of rhabdomyomas, and 50% of myxomas). When ≤2 differential diagnoses were included, both reviewers reached a correct diagnosis in 86% of cases. Of 29 malignant tumors, both reviewers indicated malignancy as a single diagnosis in 52% of cases. Including ≤2 differential diagnoses, both reviewers indicated malignancy in 83% of cases. Of 6 CMR sequences examined, acquisition of first-pass perfusion and late gadolinium enhancement were independently associated with a higher likelihood of a single correct diagnosis. CONCLUSIONS: CMR of cardiac masses in children leads to an accurate diagnosis in most cases. A comprehensive imaging protocol is associated with higher diagnostic accuracy.

Myocardial involvement in children with post-COVID multisystem inflammatory syndrome: a cardiovascular magnetic resonance based multicenter international study-the CARDOVID registry.

BACKGROUND: Recent evidence shows an association between coronavirus disease 2019 (COVID-19) infection and a severe inflammatory syndrome in children. Cardiovascular magnetic resonance (CMR) data about myocardial injury in children are limited to small cohorts. The aim of this multicenter, international registry is to describe clinical and cardiac characteristics of multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19 using CMR so as to better understand the real extent of myocardial damage in this vulnerable cohort. METHODS AND RESULTS: Hundred-eleven patients meeting the World Health Organization criteria for MIS-C associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), having clinical cardiac involvement and having received CMR imaging scan were included from 17 centers. Median age at disease onset was 10.0 years (IQR 7.0-13.8). The majority of children had COVID-19 serology positive (98%) with 27% of children still having both, positive serology and polymerase chain reaction (PCR). CMR was performed at a median of 28 days (19-47) after onset of symptoms. Twenty out of 111 (18%) patients had CMR criteria for acute myocarditis (as defined by the Lake Louise Criteria) with 18/20 showing subepicardial late gadolinium enhancement (LGE). CMR myocarditis was significantly associated with New York Heart Association class IV (p = 0.005, OR 6.56 (95%-CI 1.87-23.00)) and the need for mechanical support (p = 0.039, OR 4.98 (95%-CI 1.18-21.02)). At discharge, 11/111 (10%) patients still had left ventricular systolic dysfunction. CONCLUSION: No CMR evidence of myocardial damage was found in most of our MIS-C cohort. Nevertheless, acute myocarditis is a possible manifestation of MIS-C associated with SARS-CoV-2 with CMR evidence of myocardial necrosis in 18% of our cohort. CMR may be an important diagnostic tool to identify a subset of patients at risk for cardiac sequelae and more prone to myocardial damage. CLINICAL TRIAL REGISTRATION: The study has been registered on ClinicalTrials.gov, Identifier NCT04455347, registered on 01/07/2020, retrospectively registered.

COVID-19 Vaccination-Associated Myocarditis in Adolescents.

OBJECTIVES: In this study, we aimed to characterize the clinical presentation, short-term prognosis, and myocardial tissue changes as noted on cardiovascular magnetic resonance (CMR) or cardiac MRI in pediatric patients with coronavirus disease 2019 vaccination-associated myocarditis (C-VAM). METHODS: In this retrospective multicenter study across 16 US hospitals, patients <21 years of age with a diagnosis of C-VAM were included and compared with a cohort with multisystem inflammatory syndrome in children. Younger children with C-VAM were compared with older adolescents. RESULTS: Sixty-three patients with a mean age of 15.6 years were included; 92% were male. All had received a messenger RNA vaccine and, except for one, presented after the second dose. Four patients had significant dysrhythmia; 14% had mild left ventricular dysfunction on echocardiography, which resolved on discharge; 88% met the diagnostic CMR Lake Louise criteria for myocarditis. Myocardial injury as evidenced by late gadolinium enhancement on CMR was more prevalent in comparison with multisystem inflammatory syndrome in children. None of the patients required inotropic, mechanical, or circulatory support. There were no deaths. Follow-up data obtained in 86% of patients at a mean of 35 days revealed resolution of symptoms, arrhythmias, and ventricular dysfunction. CONCLUSIONS: Clinical characteristics and early outcomes are similar between the different pediatric age groups in C-VAM. The hospital course is mild, with quick clinical recovery and excellent short-term outcomes. Myocardial injury and edema are noted on CMR. Close follow-up and further studies are needed to understand the long-term implications and mechanism of these myocardial tissue changes.

Six Month Follow-up of Patients With Multi-System Inflammatory Syndrome in Children.

BACKGROUND AND OBJECTIVES: Myocardial dysfunction and coronary abnormalities are prominent features of multisystem inflammatory syndrome in children (MIS-C). In this study we aim to evaluate the early and midterm outcomes of MIS-C. METHODS: This is a longitudinal 6-month cohort study of all children admitted and treated for MIS-C from April 17 to June 20, 2020. Patients were followed ∼2 weeks, 8 weeks, and 6 months postadmission, with those with coronary aneurysms evaluated more frequently. RESULTS: Acutely, 31 (62%) patients required intensive care with vasoactive support, 26 (52%) had left ventricular (LV) systolic dysfunction, 16 (32%) had LV diastolic dysfunction, 8 (16%) had coronary aneurysms (z score ≥2.5), and 4 (8%) had coronary dilation (z score <2.5). A total of 48 patients (96%) received immunomodulatory treatment. At 2 weeks, there was persistent mild LV systolic dysfunction in 1 patient, coronary aneurysms in 2, and dilated coronary artery in 1. By 8 weeks through 6 months, all patients returned to functional baseline with normal LV systolic function and resolution of coronary abnormalities. Cardiac MRI performed during recovery in select patients revealed no myocardial edema or fibrosis. Some patients demonstrated persistent diastolic dysfunction at 2 weeks (5, 11%), 8 weeks (4, 9%), and 6 months (1, 4%). CONCLUSIONS: Children with MIS-C treated with immunomodulators have favorable early outcomes with no mortality, normalization of LV systolic function, recovery of coronary abnormalities, and no inflammation or scarring on cardiac MRI. Persistence of diastolic dysfunction is of uncertain significance and indicates need for larger studies to improve understanding of MIS-C. These findings may help guide clinical management, outpatient monitoring, and considerations for sports clearance.

Multisystem inflammatory syndrome in children (MIS-C) and the prothrombotic state: Coagulation profiles and rotational thromboelastometry in a MIS-C cohort.

BACKGROUND: Adults infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have had high rates of thrombosis. A novel condition in children infected with SARS-CoV-2, multisystem inflammatory syndrome in children (MIS-C), has limited data on their prothrombotic state or need for thromboprophylaxis. OBJECTIVES: We aimed to analyze the prothrombotic state using coagulation profiles, rotational thromboelastometry (ROTEM) parameters and clinical outcomes, to determine if this could aid in risk stratification for thromboprophylaxis. METHODS: This analysis included patients (<21 years of age) with a diagnosis of MIS-C (n = 40) and controls (presenting with suspicion of MIS-C but later ruled out; n = 26). RESULTS: MIS-C patients had higher levels of inflammatory markers including D-dimer (p < .0001), compared with controls, along with evidence of hypercoagulability on ROTEM with elevated evaluation of fibrinogen activity (FIBTEM) maximum clot firmness (MCF) (p < .05). For MIS-C patients with D-dimers >1000 ng/ml, there was a significant correlation of FIBTEM MCF (p < .0001) with a mean value of 37.4 (standard deviation 5.1). D-dimer >2144 ng/ml was predictive of intensive care unit admission (area under the curve [AUC] 0.80; 95% confidence interval, 0.60-0.99; p < .01; sensitivity: 82%, specificity: 75%), and elevated FIBTEM MCF (AUC 1 for >2500 ng/ml). MIS-C patients (50%) received enoxaparin thromboprophylaxis (in addition to aspirin) with significant improvement in their inflammatory and ROTEM parameters upon outpatient follow-up; none developed symptomatic thrombosis. CONCLUSIONS: Despite an observed prothrombotic state, none of the MIS-C patients (on aspirin alone or in combination with enoxaparin) developed symptomatic thrombosis. ROTEM, in addition to coagulation profiles, may be helpful to tailor thromboprophylaxis in critically ill MIS-C patients.

Society for Cardiovascular Magnetic Resonance 2019 Case of the Week series.

The Society for Cardiovascular Magnetic Resonance (SCMR) is an international society focused on the research, education, and clinical application of cardiovascular magnetic resonance (CMR). The SCMR web site ( https://www.scmr.org ) hosts a case series designed to present case reports demonstrating the unique attributes of CMR in the diagnosis or management of cardiovascular disease. Each clinical presentation is followed by a brief discussion of the disease and unique role of CMR in disease diagnosis or management guidance. By nature, some of these are somewhat esoteric, but all are instructive. In this publication, we provide a digital archive of the 2019 Case of the Week series as a means of further enhancing the education of those interested in CMR and as a means of more readily identifying these cases using a PubMed or similar search engine.

Role of a Pediatric Cardiologist in the COVID-19 Pandemic.

Coronavirus disease 2019 (COVID-19) has affected patients across all age groups, with a wide range of illness severity from asymptomatic carriers to severe multi-organ dysfunction and death. Although early reports have shown that younger age groups experience less severe disease than older adults, our understanding of this phenomenon is in continuous evolution. Recently, a severe multisystem inflammatory syndrome in children (MIS-C), with active or recent COVID-19 infection, has been increasingly reported. Children with MIS-C may demonstrate signs and symptoms of Kawasaki disease, but also have some distinct differences. These children have more frequent and severe gastrointestinal symptoms and are more likely to present with a shock-like presentation. Moreover, they often present with cardiovascular involvement including myocardial dysfunction, valvulitis, and coronary artery dilation or aneurysms. Here, we present a review of the literature and summary of our current understanding of cardiovascular involvement in children with COVID-19 or MIS-C and identifying the role of a pediatric cardiologist in caring for these patients.

Cardiac Dysfunction and Shock in Pediatric Patients With COVID-19.

Coronavirus disease-2019 (COVID-19) has been reported to cause significant morbidity in adults, with reportedly a lesser impact on children. Cardiac dysfunction has only been described in adults thus far. We describe 3 cases of previously healthy children presenting with shock and COVID-19-related cardiac inflammation. (Level of Difficulty: Intermediate.).

A Case of Persistent Left Superior Vena Cava and Left Pulmonary Venous Drainage to the Coronary Sinus.

We report a case of a persistent left superior vena cava draining to the right atrium via the coronary sinus in conjunction with partial anomalous pulmonary venous return of the left pulmonary veins to the coronary sinus. Although a persistent left superior vena cava is typically of little clinical consequence, in this case, it complicated surgical repair of the congenital heart disease. Successful repair of this unusual combination of systemic and pulmonary venous anomalies required a combination of two well-described surgical techniques.

Examining the Utility of Coronary Artery Lack of Tapering and Perivascular Brightness in Incomplete Kawasaki Disease.

BACKGROUND: In 2017, the AHA published revised guidelines for the diagnosis of Kawasaki disease (KD). In the absence of compelling data supporting or refuting the utility of lack of tapering (LT) and perivascular brightness (PB), expert panel consensus removed LT and PB from consideration. We hypothesize that LT and PB are unreliable, subjective findings, non-specific to KD, which can be seen in systemic febrile illnesses without KD and in normal controls. METHODS: We performed a single-center retrospective study from 1/2008 to 12/2016. De-identified coronary artery (CA) echocardiographic clips from patients 0-10 years old were interpreted blindly by six pediatric cardiologists. Subjects were grouped as follows: (1) healthy: afebrile with benign murmur, (2) KD: IVIG treatment, 4-5 clinical criteria at presentation, (3) incomplete KD (iKD): IVIG, 1-3 clinical criteria, (4) Febrile: ≥3 days of fever, no IVIG, KD not suspected. The presence or absence of LT and PB was recorded. Inter-rater and intra-rater reliabilities were analyzed using intra-class correlation coefficient, Fleiss' Kappa and Cohen's Kappa coefficients. RESULTS: We interpreted 117 echocardiograms from healthy (27), KD (30), iKD (32), and febrile (28) subjects. Analysis showed moderate agreement in CA z score measurements. LT and PB were observed by most readers in control groups. LT exhibited fair inter-reader agreement (reliability coefficient 0.36) and PB slight inter-reader agreement (reliability coefficient 0.13). Intra-rater reliability was inconsistent for both parameters. CONCLUSIONS: LT and PB are subjective, poorly reproducible features that can be seen in febrile patients without KD and in healthy children.

Surgical Angioplasty of Stenotic Left Main Coronary Artery 15 Years After ALCAPA Repair.

Studies regarding long-term results after repair of anomalous left main coronary artery from the pulmonary artery (ALCAPA) have mainly focused on survival rates, left ventricular function, and mitral valve function. The development of left main coronary stenosis following repair has been infrequently reported and its incidence unknown. Optimal therapy is also not known. Here we report the use of surgical angioplasty to achieve revascularization of a stenotic left main coronary artery in a patient with ALCAPA who had undergone coronary transfer 15 years earlier.

Comparison of Patients Undergoing Surgical Versus Transcatheter Pulmonary Valve Replacement: Criteria for Referral and Mid-Term Outcome.

Pulmonary regurgitation and/or stenosis (PS) is challenging in patients with congenital heart defects. Our aim was to identify if criteria for referral were different between surgical (SPVR) and transcatheter pulmonary valve replacement (TPVR) populations, and to further assess if any baseline differences influence the resultant ventricular remodeling at medium-term follow-up. Retrospective chart review of patients post-SPVR or TPVR at our center from 2013 to 2015 was conducted. Volumetric data from cardiac magnetic resonance (CMR), 1 year before and 1 year after PVR was obtained. PS was defined as peak-peak gradient ≥35 mmHg by catheterization or peak gradient ≥50 mmHg by echocardiography. Thirty patients underwent PVR: 15 SPVR and 15 TPVR (1 hybrid). The indications for SPVR referral were: 2+ CMR parameters in 80% of patients; decreased left ventricular ejection fraction and hemodynamic findings and/or abnormal exercise stress test in 20%. The indications for TPVR referral were predominantly symptoms ± hemodynamic findings in 66% of patients, 2+ CMR findings in 44% of patients. At referral, SPVR group had significantly larger right ventricular (RV) volumes than TPVR group. Biventricular function was not significantly different. Post-PVR, both groups had significantly decreased RV volumes and increased LV diastolic volumes. The SPVR group improved LV cardiac output and biventricular function whereas TPVR group had no significant improvement. The patients in the SPVR group were mostly referred based on CMR volumetric criteria, whereas the patients in the TPVR group were mostly referred due to exercise intolerance with only occasional abnormalities on CMR. 1 year after PVR, both groups had near-normal biventricular volumes and function irrespective of characteristics at referral.

Characterization of cardiac tumors in children by cardiovascular magnetic resonance imaging: a multicenter experience.

OBJECTIVES: The aim of this study was to report the results of an international multicenter experience of cardiac magnetic resonance imaging (MRI) evaluation of cardiac tumors in children, each with histology correlation or a diagnosis of tuberous sclerosis, and to determine which characteristics are predictive of tumor type. BACKGROUND: Individual centers have relatively little experience with diagnostic imaging of cardiac tumors in children, because of their low prevalence. The accuracy of cardiac MRI diagnosis on the basis of a pre-defined set of criteria has not been tested. METHODS: An international group of pediatric cardiac imaging centers was solicited for case contribution. Inclusion criteria comprised: 1) age at diagnosis ≤18 years; 2) cardiac MRI evaluation of cardiac tumor; and 3) histologic diagnosis or diagnosis of tuberous sclerosis. Data from the cardiac MRI images were analyzed for mass characteristics. On the basis of pre-defined cardiac MRI criteria derived from published data, 3 blinded investigators determined tumor type, and their consensus diagnoses were compared with histologic diagnoses. RESULTS: Cases (n = 78) submitted from 15 centers in 4 countries had the following diagnoses: fibroma (n = 30), rhabdomyoma (n = 14), malignant tumor (n = 12), hemangioma (n = 9), thrombus (n = 4), myxoma (n = 3), teratoma (n = 2), and paraganglioma, pericardial cyst, Purkinje cell tumor, and papillary fibroelastoma (n = 1, each). Reviewers who were blinded to the histologic diagnoses correctly diagnosed 97% of the cases but included a differential diagnosis in 42%. Better image quality grade and more complete examination were associated with higher diagnostic accuracy. CONCLUSIONS: Cardiac MRI can predict the likely tumor type in the majority of children with a cardiac mass. A comprehensive imaging protocol is essential for accurate diagnosis. However, histologic diagnosis remains the gold standard, and in some cases malignancy cannot be definitively excluded on the basis of cardiac MRI images alone.

Adult definitions for dyssynchrony are inappropriate for pediatric patients.

BACKGROUND: Cardiac resynchronization therapy (CRT) is a promising approach to improve cardiac function in children in heart failure with cardiomyopathy. Cardiac timing measures in pediatrics are typically based on age and heart rate. However, pediatric CRT studies to date have used adult based timing cutoff values. We investigated the applicability of using these adult standards in pediatric patients with normal hearts. METHODS: We studied 88 outpatients referred for cardiac evaluation who had a normal cardiac evaluation. Subjects had 12 lead EKG and normal echocardiogram. Patients with known heart disease or abnormal rhythms were excluded. 2D echo and Doppler including color tissue Doppler imaging (TDI, Vivid 7 GE Ultrasound, Norway) were obtained. TDI was performed on three standard apical views (four chamber, two chamber, and long axis). Longitudinal dyssynchrony was determined from (1) Yu index--standard deviation of differences in timing of peak TDI velocity of all 12 basal and mid LV wall segments, adult cutoff >32 ms and (2) opposing wall difference (OWD) in timing of peak TDI velocity of 12 LV wall segments, adult cutoff >65 ms. Radial dyssynchrony was determined from differences in timing of peak radial strain between anterior-septal and posterior LV segments from speckle tracking of 2D LV views, adult cutoff >130 ms. RESULTS: Median age was 11.5 years; median heart rate was 74.5. Longitudinal dyssynchrony was present in 40% of normals based on Yu index, and in 43% based on OWD. No child had Radial dyssynchrony. CONCLUSIONS: This pilot study of children with normal hearts suggests that current adult CRT dyssynchrony cutoff values are inappropriate in the pediatric population.